Drafting method

ABSTRACT

Method of drafting sliver which has at least some of the staple fibers therein longer than the distance between center lines of adjacent pairs of rolls in a drafting system.

United States Patent 1191 1111 4 3,778,995 Sanders 1 1 Dec. 18, 1973 [54] DRAWING METHOD FOREIGN PATENTS OR APPLICATIONS a Inventor! Grady Sanders, Spartanburg, 893,622 10/1953 Germany 19/260 560.635 4/1944 Great Britain... 19/257 1 898,418 11/1953 Germany 19/236 [73] Assgnee' Demng Research 742,141 11/1943 Germany 19/244 Corporation, Spartanburg, SC.

22 Filed: Sept. 9, 1971 Primary ExammerDorsey Newton PP 179,022 Attorney-Norman C. Armitage et a1.

[52] U.S. Cl 57/156, 57/36, 57/90, 19/258, 19/244 1 57 ABSTRACT [51] Int. Cl. 002g 3/00, DOlh 5/00 l of Search Method f draftin g sliver which has at least some of 19/288 7 the staple fibers therein longer than the distance be 90 tween center lines of adjacent pairs of rolls in a draft- Q I [56] References Cited mg sys em a UNITED STATES PATENTS 1 Claim, 3 Drawing Figures 2,140,535 12/1938 McGill et a1 19/236 PATENTEDUEBI a ma NVENTOR. GRADY H. SANDERS ATTORNEY I PATENTEDUEBI a ma SHEET 2 OF 2 FIG, -3

INV EN TOR. GRADY H. SANDERS ATTORNEY DRAFTING METHOD ln recent years the textile industry has gone into production of yarn which contains longer and longer staple fibers. This yarn is either a blend of long and short staple fibers or composed of all long staple fibers. It is very difficult todraft long fibers on spinning frames on the cotton system since the ratch or distance between pairs of drafting rolls is too short to draft long staple fibers of 3" ormore length. Various techniques have been tried on these spinning frames but involved expensive modifications of the frame and resulted in poor quality yarn.

Therefore it is an object of the invention to provide a method and apparatus to draft long staple fibers which does not involve expensive modification to the spinning frame and provides a high quality yarn.

Other objects and advantages of the invention will become clearly apparent as the specification proceeds to describe the invention with reference to the accompanying drawings, in which:

FIG. 1 is a top view of the new andimproved drafting arrangement;

FIG. 2 is a cross-sectional view of the drafting arrangement shown in FIG. 1; and

PK]. 3 is a view showing the cradle side plate mounting in relation to the front and middle drafting rolls.

Looking now to the drawings, the drafting arrangement comprises three sets of drafting rolls, namely, back rolls l and 12, middle rolls l4 and 16 and front rolls l8 and 20. Each set of rolls has the rolls in nip forming engagement with each set of rolls being driven by any suitable means, such as motors 21, 23, and 25, schematically presented in FIG. 1, at a faster rate than the preceding set of rolls to provide the desired degree of drafting of the fibers in the zones between the respective pairs of rolls.

As pointed out previously, the purpose of this invention is to provide a method and apparatus to draft long staple fibers on a conventionalcotton spinning frame on which the normal ratch is about 4 inches from the center line of the rear rolls to the center line of the front rolls. To accomplish this a new and novel drafting cradle is provided. The drafting cradle has a pair ofside walls 22 and 24 each having a notch 26 to engage the lower front roll and another surface 28 to engage the lower middle roll 16. Interconnected between the side walls 22 and 24 is an apron guiding member 30 which has a concave surface 32 engaging the surface of the roll 16 and two apron reversing portions 34and 38. The apron reversing portions are connected by an apron guiding surface 40 to guide the apron 42 from apron reversing portion 34 to apron reversing portion 38. Another apron guiding surface 44 extends between tabs 56 and 58 to aid in maintaining the cradle walls 22 and 24 in a predetermined spaced relationship. Each of the sidewalls has an oval shaped notch 60 therein to accommodatea dowel 62 attached to the side of the wardly in the notches 46 and vice versa, thereby providing ease of adjustment of the tensor opening without replacement of parts.

In the upper portion of the cradle walls 22 and 24 further notches 65 to accommodate the stub shafts 66 and 68 attached to bar member 70. Tabs 72 and 74, i i

like tabs 56 and 58, also aid in, maintaining the spaced relationship of the side walls 22 and 24. Another notch 76 is located in each of the bottom portions of the cradle side walls 22 and 24 to accommodate the bar member 78 for further support of the spaced relationships of the cradle walls.

The cradle walls 22 and 24 are eachmolded with a hook portion 80 to define a cavity into which the upper roll is guided into nip forming relationship with roll 16 by the weight arm (not shown) of the drafting system. a i

In operation a sliver or roving of fibers F is supplied into the nip of rear rolls 10, 12 through a conventional condenser 81. From the nip of rolls 10, 12 the fibers F wrap partially around roll 10 and are directed upwardly over bar-70. From the bar 70 the fibers F pass downwardly into the nip of the middle rolls 14, 16. At the nip of rolls 14, 16 the drafting aprons contact the fibers F and aid in guiding the fibers around the roll 14 backwardly to and around the reversing portion 34 of the apron guiding member 54 and down the apron guiding surface 40 into the nip of front rolls 18, 20. From the nip of rolls 18, 20 the fibers are twisted into yarn Y by the conventional ring R and traveler T and taken up on bobbin B.

It should be noted that the fiber path between the nip of rolls 10, 12 and rolls [4, 16 as well as the fiber path U between rolls 14, 16 and 18, 20 is considerably longer than the normal fiber path which normally would be directly from one nip to the next adjacent nip. Therefore, much longer fibers can be drafted without the individual fibers being caught between two adjacent nips and being broken due to the differential speed of the rolls.

having at least three sets of drafting rolls with each set, of rolls having a top roll-and bottom roll in nip forming relationship and with the first set of rolls being spaced from the second set of rolls and the second set of rolls being spaced from the third set of rolls with the top rolls of each set having a centerline which is in substantially a straight line relationship with centerlines of the a other top rolls of each set comprising the steps of: supplying fiber to be drafted into the nip ofthe first set of drafting rolls, directing the fiber from the nip of the first set of drafting rolls around at least of the periphery of said first top roll in an upward direction, then directing the fiber downward into the nip of the second set of rolls, directing the fiber from the nip of the second set of rolls around at least of the periphery of the top roll of the second set of rolls and then in a direction toward the first set of rolls, reversing the flow of fibers at least 180 and directing the fiber into the nip of the third set of rolls, and twisting the fibers supplied from the nip of the third set of drafting rolls.

are 

1. A method of drafting fibers in a drafting system having at least three sets of drafting rolls with each set of rolls having a top roll and bottom roll in nip forming relationship and with the first set of rolls being spaced from the second set of rolls and the second set of rolls being spaced from the third set of rolls with the top rolls of each set having a centerline which is in substantially a straight line relationship with centerlines of the other top rolls of each set comprising the steps of: supplying fiber to be drafted into the nip of the first set of drafting rolls, directing the fiber from the nip of the first set of drafting rolls around at least 90* of the periphery of said first top roll in an upward direction, then directing the fiber downward into the nip of the second set of rolls, directing the fiber from the nip of the second set of rolls around at least 180* of the periphery of the top roll of the second set of rolls and then in a direction toward the first set of rolls, reversing the flow of fibers at least 180* and directing the fiber into the nip of the third set of rolls, and twisting the fibers supplied from the nip of the third set of drafting rolls. 